Industrial vehicle

ABSTRACT

An engine exhaust system is accommodated in a counterweight portion without reducing either the efficiency of cooling by a radiator or the efficiency of purifying exhaust gas by an exhaust gas purification device. A body has a work device provided at the front and the counterweight portion at the rear. A ventilation path provided in the counterweight portion includes an elevated part formed between a bottom of a front portion and a bottom of a rear portion. The purification device and a muffler are disposed in the rear portion of the ventilation path so as to be positioned one above the other with the purification device lying above the muffler and having an upper portion protruding above the bottom of the front portion of the ventilation path. A windbreak plate made from a heat insulating material is disposed forward from the purification device so as to face the latter.

TECHNICAL FIELD

The present invention relates to industrial vehicles, particularly to anindustrial vehicle, such as a forklift or a shovel loader, whichincludes an engine as a power source and has a work device attached atthe front of a body.

BACKGROUND ART

Some of the industrial vehicles such as a forklift and a shovel loaderinclude diesel engines as power sources. Incidentally, emissions controlis applied to diesel engine vehicles, and it is obligatory to reducehazardous substances in exhaust gas, such as particulate matter (PM),sulfur oxide, and nitrogen oxide (NOx), to standard values or lower.Accordingly, industrial vehicles equipped with diesel engines also haveexhaust gas purification devices attached on the upstream side relativeto exhaust pipe mufflers of the engines.

For example, conventional forklifts equipped with diesel engines havework devices provided at the front of bodies, and also havecounterweight portions provided at the rear of the bodies in order tobalance loads on the work devices, and the engines are attached to thebodies and positioned forward from the counterweight portions (see, forexample, Patent Documents 1 and 2). Moreover, provided in thecounterweight portions are ventilation paths extending in the front-reardirection of the bodies.

Furthermore, there are radiators disposed rearward from the engines soas to be positioned immediately before front end openings of theventilation paths or at the front of the ventilation paths, and alsodisposed between the engines and the radiators are radiator fans forcooling the radiators. Accordingly, airflows generated by rotation ofthe radiator fans are exhausted through the ventilation paths to theoutside of the bodies.

Further, the forklifts include exhaust pipes, exhaust gas purificationdevices and mufflers, in which the exhaust pipes are supported by thebodies, connected to the engines at one end, and protrude from the rearof the bodies to the outside at the other end, and the exhaust gaspurification devices and the mufflers are provided at some positionsalong the exhaust pipes. Typically, the exhaust gas purification deviceand the muffler have a cylindrical outer shape, and constitute arelatively large component unit in the forklift in the case where theforklift is small.

Still further, the operating temperature of the exhaust gas purificationdevice is considerably high (about 400 to 800° C.), and in addition, theexhaust gas purification device is designed to be heated by exhaust gasand therefore is preferably disposed as close as possible to an exhaustmanifold of the engine.

Accordingly, there is an issue as to where in the body to dispose anengine exhaust system, which consists of the exhaust pipe, the exhaustgas purification device, and the muffler, and in this case, for reasonsconcerned with the structure of the forklift, it is desirable to notchange the existing arrangement of the engine, the radiator, theradiator fan, and the counterweight portion on the body (i.e., thepositional relationship therebetween).

Therefore, in the conventional art, considering the downsizing of thebody, the ensuring of the driver's view, prevention of burns to thedriver, easy maintenance of the exhaust gas purification device, etc.,the engine exhaust system is accommodated in the counterweight portion,and further, the exhaust gas purification device is disposed so as toface the back of the radiator (see, for example, Patent Documents 1 and2).

However, although this configuration allows the exhaust gas purificationdevice to be cooled by cooling air directly blowing from the radiatorfan that is rotating, the radiator is heated by being subjected toradiation heat straight from the exhaust gas purification device,resulting in an issue of compromising both the efficiency of cooling anengine coolant by the radiator and the efficiency of purifying exhaustgas by the exhaust gas purification device.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Laid-Open Patent Publication No. H08-312335

Patent Document 2: Japanese Laid-Open Patent Publication No. 2012-106836

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

Therefore, the present invention addresses a problem of allowing anengine exhaust system to be accommodated in a counterweight portionwithout reducing either the efficiency of cooling by a radiator or theefficiency of purifying exhaust gas by an exhaust gas purificationdevice.

Solution to the Problems

To solve the problem, the present invention provides an industrialvehicle including a work device attached at a front of a body, acounterweight portion for balancing a load on the work device, thecounterweight portion being disposed at a rear of the body and having aventilation path provided therein so as to extend in a front-reardirection of the body, an engine attached to the body as a power sourceand disposed forward from the counterweight portion, a radiator disposedrearward from the engine so as to be positioned immediately before afront end opening of the ventilation path or at a front portion of theventilation path, a radiator fan for cooling the radiator, the radiatorfan being disposed between the engine and the radiator and allowing anairflow generated by rotation of the radiator fan to be exhausted to theoutside of the body through the ventilation path, an exhaust pipesupported by the body, connected to the engine at one end, andprotruding from the rear of the body to the outside at the other end,and an exhaust gas purification device and a muffler provided at somepositions along the exhaust pipe, in which, the exhaust gas purificationdevice and the muffler are disposed rearward from the radiator in theventilation path, either one above the other or side by side in aright-left direction of the body, a windbreak plate for preventing theairflow from blowing onto the exhaust gas purification device isdisposed between the radiator and the exhaust gas purification device soas to face the exhaust gas purification device, and the windbreak plateis formed from a heat insulating material.

In accordance with a preferred embodiment of the present invention, anelevated part is formed between bottoms of the front and rear portionsof the ventilation path, whereby the bottom of the rear portion is lowerthan the bottom of the front portion, the exhaust gas purificationdevice and the muffler are disposed in the rear portion of theventilation path so as to be positioned one above the other with theexhaust gas purification device lying above the muffler and at leastpartially protruding above the bottom of the front portion of theventilation path, and the windbreak plate is erected on the bottom ofthe front portion such that the windbreak plate has an upper end surfacepositioned higher than an upper end surface of the exhaust gaspurification device.

In accordance with another preferred embodiment of the presentinvention, the exhaust gas purification device and the muffler aredisposed one above the other with the exhaust gas purification devicelying below the muffler, and the windbreak plate is erected on thebottom of the ventilation path such that the windbreak plate has anupper end surface positioned higher than an upper end surface of theexhaust gas purification device. In accordance with still anotherpreferred embodiment of the present invention, at least an upper portionof the windbreak plate is bent or curved toward the exhaust gaspurification device. In accordance with yet another preferred embodimentof the present invention, both the exhaust gas purification device andthe muffler have a cylindrical outer shape and extend in the right-leftdirection of the body.

In accordance with yet another preferred embodiment of the presentinvention, an elevated part is formed between bottoms of the front andrear portions of the ventilation path, whereby the bottom of the rearportion is lower than the bottom of the front portion, the exhaust gaspurification device and the muffler are disposed in the rear portion ofthe ventilation path so as to be positioned side by side in theright-left direction of the body, with the exhaust gas purificationdevice at least partially protruding above the bottom of the frontportion of the ventilation path, and the windbreak plate is erected onthe bottom of the front portion such that the windbreak plate has anupper end surface positioned higher than an upper end surface of theexhaust gas purification device. In accordance with yet anotherpreferred embodiment of the present invention, both the exhaust gaspurification device and the muffler have a cylindrical outer shape andextend vertically. In accordance with yet another preferred embodimentof the present invention, the industrial vehicle is a forklift.

Effect of the Invention

In accordance with the present invention, the exhaust gas purificationdevice and the muffler of the industrial vehicle are disposed rearwardfrom the radiator in the ventilation path within the counterweightportion, either one above the other or side by side in the right-leftdirection of the body, the windbreak plate is disposed between theradiator and the exhaust gas purification device so as to prevent anairflow caused by the radiator fan from blowing onto the exhaust gaspurification device, and further, the windbreak plate is formed from aheat insulating material. Therefore, the engine exhaust system (i.e.,the exhaust pipe, the exhaust gas purification device, and the muffler)of the industrial vehicle can be collectively accommodated in thecounterweight portion, and at the same time, while the industrialvehicle is being driven, neither is the exhaust gas purification devicesubjected to cooling air directly from the radiator fan, nor is theradiator subjected to radiation heat straight from the exhaust gaspurification device, whereby unnecessary cooling of the exhaust gaspurification device and unnecessary heating of the radiator areminimized, so that the efficiency of purifying exhaust gas by theexhaust gas purification device and the efficiency of cooling by theradiator are not reduced. Moreover, the ventilation path in thecounterweight portion is utilized as the space to accommodate theexhaust gas purification device and the muffler, whereby there is almostno need to change existing structures of industrial vehicles, so thatthe present invention can also be applied to existing industrialvehicles at extremely low costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view illustrating the general configuration of anindustrial vehicle in the form of a forklift according to an embodimentof the present invention.

FIG. 2 is a cross-sectional view taken along the direction of thecentral axis of a body of the forklift shown in FIG. 1, outlining thestructure of a counterweight portion.

FIG. 3 is an oblique view illustrating main internal components of thecounterweight portion shown in FIG. 2.

FIG. 4A and FIG. 4B provide similar views to FIG. 2 and illustratesvariants of a windbreak plate.

FIG. 5A and FIG. 5B provide views illustrating variants of theembodiment shown in FIG. 1.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of the present invention will bedescribed with reference to the accompanying drawings. FIG. 1 is a sideview schematically illustrating the general configuration of anindustrial vehicle according to an embodiment of the present invention.In this embodiment, the industrial vehicle is in the form of a forklift,as shown in FIG. 1. Referring to FIG. 1, the forklift has a fork 2attached at the front of a body 1 as a work device, and a counterweightportion 3 disposed at the rear of the body 1 in order to balance a loadon the fork 2. In addition, provided forward from the counterweightportion 3 on the body 1 is an engine (diesel engine) 4 serving as apower source.

FIG. 2 is a cross-sectional view taken along the direction of thecentral axis of the body 1 of the forklift, outlining the structure ofthe counterweight portion 3, and FIG. 3 is an oblique view illustratingmain internal components of the counterweight portion shown in FIG. 2.Referring to FIG. 2, the counterweight portion 3 has an upper wall 3 a,a rear wall 3 b, and left and right side walls (not shown), and providedin the counterweight portion 3 is a ventilation path 5 extending in thefront-rear direction of the body 1 and having a front end openingserving as an air inlet 5 a and a rear end opening serving as an airoutlet 5 b. The air outlet 5 b is provided in the rear wall 3 b of thecounterweight portion 3.

The ventilation path 5 has an elevated part 14 formed between a bottom 6a of a front portion 6 and a bottom of a rear portion 7, so that thebottom of the rear portion 7 is lower than the bottom 6 a of the frontportion 6. Note that in this embodiment, the bottom 6 a of the frontportion 6 of the ventilation path 5 is formed by a part of the surfaceof a counterweight or body 9, and the ventilation path 5 is open at thebottom of the rear portion 7.

Disposed in the front portion 6 of the ventilation path 5 is a radiator8 for cooling an engine coolant. The radiator 8 is erected on the bottom6 a of the front portion 6 of the ventilation path 5 so as to face theair inlet 5 a and the air outlet 5 b. Note that in this embodiment,although the radiator 8 is disposed in the front portion 6 of theventilation path 5, if necessary, the radiator 8 may be disposedrearward from the engine 4 so as to be positioned immediately before theair inlet 5 a of the ventilation path 5.

Disposed between the engine 4 and the radiator 8 is a radiator fan 10for cooing the radiator 8. The radiator fan 10 is positioned so as toface the front of the radiator 8, and has a rotating shaft 10 a coupledto the engine 4. The radiator fan 10 is rotationally driven by theengine 4. Accordingly, an airflow is generated by rotation of theradiator fan 10 and exhausted through the ventilation path 5 to theoutside of the body 1 from the air outlet 5 b.

The forklift further includes an exhaust pipe 11, an exhaust gaspurification device 12, and a muffler 13, in which the exhaust pipe 11is supported by the body 1, connected to the engine 4 at one end, andprotrudes from the rear of the body 1 to the outside at the other end,and the exhaust gas purification device 12 and the muffler 13 areprovided at some positions along the exhaust pipe 11. The exhaust gaspurification device 12 includes, for example, a diesel particulatefilter (DPF), a diesel oxidation catalyst (DOC), and so on.

In this embodiment, both the exhaust gas purification device 12 and themuffler 13 have a cylindrical outer shape. Moreover, the exhaust gaspurification device 12 and the muffler 13 discretely extend in the rearportion 7 of the ventilation path 5 in the right-left direction of thebody 1, and are positioned one above the other with the exhaust gaspurification device 12 lying above the muffler 13 and at least partially(in this embodiment, the upper half) protruding above the bottom 6 a ofthe front portion 6 of the ventilation path 5.

Although not shown, the exhaust gas purification device 12 and themuffler 13 are fixed to the body 1 at predetermined discrete positions,either directly by bolts and nuts or via appropriate supporting members.

Disposed between the radiator 8 and the exhaust gas purification device12 is a windbreak plate 15 for preventing an airflow generated byrotation of the radiator fan 10 from blowing onto the exhaust gaspurification device 12, and the windbreak plate 15 is positioned so asto face the exhaust gas purification device 12. The windbreak plate 15is formed from a heat insulating material. In this embodiment, thewindbreak plate 15 is erected on the bottom 6 a of the front portion 6of the ventilation path 5 and has an upper portion 15 a curving towardthe exhaust gas purification device 12 and an upper end surfacepositioned higher than an upper end surface of the exhaust gaspurification device 12.

In this embodiment, although the upper portion 15 a of the windbreakplate 15 curves toward the exhaust gas purification device 12, the shapeof the windbreak plate 15 is not limited by this embodiment, and thewindbreak plate IS may have any shape so long as the shape renders itpossible to prevent a cooing airflow from the radiator fan 10 fromblowing onto the exhaust gas purification device 12. For example, awindbreak plate 15′ may be configured so as to extend vertically upwardfrom the bottom 6 a of the front portion 6 of the ventilation path 5past the upper end surface of the exhaust gas purification device 12, asshown in FIG. 4A, or a windbreak plate 15″ may be configured with anupper portion 15 a″ bending toward the exhaust gas purification device12 and an upper end surface being positioned higher than an upper endsurface of the exhaust gas purification device 12, as shown in FIG. 4B.

The exhaust pipe 11 consists of a first portion 11 a, a second portion11 b, and a third portion 11 c, in which the first portion 11 a extendsfrom the engine 4 (i.e., an exhaust manifold (not shown) of the engine4) through the front portion 6 of the ventilation path 5 in thecounterweight portion 3 to one end surface 12 a of the exhaust gaspurification device 12, the second portion 11 b is on the other endsurface 12 b of the exhaust gas purification device 12 and connects theend surface 12 b of the exhaust gas purification device 12 to an endsurface 13 b of the muffler 13, and the third portion 11 c extendsdownward from the other end surface 13 a of the muffler 13 and shiftshorizontally so as to protrude to the outside from the rear wall 3 b ofthe counterweight portion 3.

In this embodiment, the tip of the exhaust pipe 11 protrudeshorizontally from the rear wall 3 b of the counterweight portion 3, butthe position at which the tip (exhaust port) of the exhaust pipe 11protrudes from the body 1 is not limited by the embodiment, and, forexample, the tip (exhaust port) of the exhaust pipe 11 may protrudeupward from the upper wall 3 a of the counterweight portion 3.

Furthermore, in this embodiment, the first to third portions 11 a to 11c of the exhaust pipe 11 are connected to the end surface 12 a or 12 bof the exhaust gas purification device 12 and/or the end surface 13 a or13 b of the muffler 13, but the positions at which the first to thirdportions 11 a to 11 c are connected to the exhaust gas purificationdevice 12 and the muffler 13 are not limited by the embodiment, and forexample, the first to third portions 11 a to 11 c may be connected tocircumferential surfaces of the ends of the exhaust gas purificationdevice 12 and the muffler 13.

In this embodiment, the ventilation path 5 of the counterweight portion3 is formed such that the bottom of the rear portion 7 of theventilation path 5 is lower than the bottom 6 a of the front portion 6,whereby the exhaust gas purification device 12 and the muffler 13 can becompactly accommodated in the space of the rear portion 7 of theventilation path 5; further, the windbreak plate 15 made from a heatinsulating material is provided between the radiator 8 and the exhaustgas purification device 12, whereby, when the forklift is being driven,neither is the exhaust gas purification device 12 subjected to coolingair directly from the radiator fan 10, nor is the radiator 8 subjectedto radiation heat straight from the exhaust gas purification device 12,so that both unnecessary cooling of the exhaust gas purification device12 and unnecessary heating of the radiator 8 can be minimized. Moreover,the exhaust system of the engine 4 can be accommodated in thecounterweight portion 3 without reducing the efficiency of purifyingexhaust gas by the exhaust gas purification device 12 and the efficiencyof cooling by the radiator 8.

Furthermore, in this configuration, the exhaust gas purification device12 is disposed near the air outlet 5 b of the ventilation path 5, andtherefore, the exhaust gas purification device 12 can be accessedreadily through the air outlet 5 b, whereby easy maintenance of theexhaust gas purification device 12 can be facilitated. In addition, therear space of the counterweight portion 3 is utilized as the space toaccommodate the exhaust gas purification device 12 and the muffler 13,thereby almost eliminating the need to change existing structures offorklifts, so that the present invention can also be applied to existingforklifts at extremely low costs.

FIG. 5A is a similar view to FIG. 3 and illustrates a variant of theembodiment shown in FIG. 1. This variant differs from the embodimentshown in FIG. 1 simply in the arrangement of the exhaust gaspurification device and the muffler. Accordingly, in FIG. 5A, the samecomponents as those shown in FIG. 1 are denoted by the same numerals,and any detailed descriptions thereof will be omitted below.

Referring to FIG. 5A, in this variant, both the exhaust gas purificationdevice 12 and the muffler 13 are disposed in the rear portion 7 of theventilation path 5 so as to extend vertically and be positioned side byside in the right-left direction of the body 1. In this case, both theexhaust gas purification device 12 and the muffler 13 protrude above thebottom 6 a of the front portion 6 of the ventilation path 5.

Provided between the radiator 8 and the exhaust gas purification device12 is a windbreak plate 16 made from a heat insulating material anderected on the bottom 6 a of the front portion 6 of the ventilation path5 so as to face the exhaust gas purification device 12. The windbreakplate 16 extends vertically upward from the bottom 6 a past the upperend surface 12 b of the exhaust gas purification device 12. This variantalso renders it possible to achieve similar effects to those achieved bythe embodiment shown in FIG. 1.

FIG. 5B is a similar view to FIG. 2 and illustrates another variant ofthe embodiment shown in FIG. 1. This variant differs from the embodimentshown in FIG. 1 simply in the structure of the ventilation path in thecounterweight portion, the arrangement of the exhaust gas purificationdevice and the muffler, the disposition of the windbreak plate, and theposition from which the exhaust pipe protrudes to the outside of thebody. Accordingly, in FIG. 5B, the same components as those shown inFIG. 1 are denoted by the same numerals, and any detailed descriptionsthereof will be omitted below.

Referring to FIG. 5B, in this variant, the lower part of thecounterweight portion 3 is occupied by a counterweight or body 9′, andthe space above the counterweight or body 9′ in the counterweightportion 3 constitutes a ventilation path 5′. Accordingly, theventilation path 5′ has a constant height almost across its length.Moreover, both the exhaust gas purification device 12 and the muffler 13are disposed rearward from the radiator 8 in the ventilation path 5′ soas to extend in the right-left direction of the body 1 and be positionedone above the other with the exhaust gas purification device 12 lyingbelow the muffler 13.

Provided between the radiator 8 and the exhaust gas purification device12 is a windbreak plate 17 made from a heat insulating material anderected on the bottom of the ventilation path 5′ so as to face theexhaust gas purification device 12. The windbreak plate 17 extendsvertically upward from the bottom of the ventilation path 5′ past theupper end surface of the exhaust gas purification device 12. In thiscase, the upper portion of the windbreak plate 17 may be curved or benttoward the exhaust gas purification device 12. Moreover, in thisvariant, the third portion 11 c of the exhaust pipe 11 extends upwardfrom one end surface 13 a of the muffler 13 so as to cross theventilation path 5′, and protrudes upward through the upper wall 3 a ofthe counterweight portion 3.

In the above embodiment, the industrial vehicle is a forklift, but theindustrial vehicle to which the present invention can be applied is notlimited to a forklift. Moreover, the present invention can be applied toany industrial vehicle so long as the industrial vehicle includes a workdevice at the front of the body and a counterweight portion at the rearof the body to balance a load on the work device.

DESCRIPTION OF THE REFERENCE CHARACTERS

-   -   1 body    -   2 fork (work device)    -   3 counterweight portion    -   3 a upper wall    -   3 b rear wall    -   4 engine    -   5, 5′ ventilation path    -   5 a, 5 a′ air inlet    -   5 b, 5 b′ air outlet    -   6 front portion    -   6 a bottom    -   7 rear portion    -   8 radiator    -   9, 9′ counterweight or body    -   10 radiator fan    -   10 a rotating shaft    -   11 exhaust pipe    -   16    -   11 a first portion    -   11 b second portion    -   11 c third portion    -   12 exhaust gas purification device    -   12 a, 12 b end surface    -   13 muffler    -   13 a, 13 b end surface    -   14 elevated part    -   15, 15′, 15″ windbreak plate    -   15 a, 15 a′, 15 a″ upper portion    -   16 windbreak plate    -   17 windbreak plate

The invention claimed is:
 1. An industrial vehicle comprising: a work device attached at a front of a body; a counterweight portion for balancing a load on the work device, the counterweight portion being disposed at a rear of the body and having a ventilation path provided therein so as to extend in a front-rear direction of the body; an engine attached to the body as a power source and disposed forward from the counterweight portion; a radiator disposed rearward from the engine so as to be positioned immediately before a front end opening of the ventilation path or at a front portion of the ventilation path; a radiator fan for cooling the radiator, the radiator fan being disposed between the engine and the radiator and allowing an airflow generated by rotation of the radiator fan to be exhausted to the outside of the body through the ventilation path; an exhaust pipe supported by the body, connected to the engine at one end, and protruding from the rear of the body to the outside at the other end; and an exhaust gas purification device and a muffler provided at some positions along the exhaust pipe, wherein: an elevated part is formed between bottoms of the front and rear portions of the ventilation path, whereby the bottom of the rear portion is lower than the bottom of the front portion, the exhaust gas purification device and the muffler are disposed in the rear portion of the ventilation path so as to be positioned side by side in the right-left direction of the body, with the exhaust gas purification device at least partially protruding above the bottom of the front portion of the ventilation path, a windbreak plate for preventing the airflow from blowing onto the exhaust gas purification device is disposed between the radiator and the exhaust gas purification device so as to face the exhaust gas purification device, the windbreak plate being formed from a heat insulating material, and the windbreak plate being erected on the bottom of the front portion such that the windbreak plate has an upper end surface positioned higher than an upper end surface of the exhaust gas purification device.
 2. The industrial vehicle according to claim 1, wherein both the exhaust gas purification device and the muffler have a cylindrical outer shape and extend vertically.
 3. The industrial vehicle according to claim 1, wherein the industrial vehicle is a forklift. 